An inclined plane makes an angle 30o with the horizontal. A groove (OA) of length 5 m cut in the plane makes an angle 30o with OX. A short smooth cylinder is free to slide down under the influence of gravity. The time taken by the cylinder to reach from A to O is : g = 10 m/s2

Answer & explanation
Correct answer: option 2
Acceleration of cylinder down the plane is : a
a = (g sin 30o) (sin 30o)
= 10 \(\frac{1}{2} \frac{1}{2}\)
= 2.5 m/s2
Time : t = \(\sqrt{\frac{2 S}{a}} = \sqrt{\frac{2*5}{2.5}}\)
t = 2 s